Associations between polymorphisms of the cystatin C gene (CST3) at 5' flanking region and exon 1 in Caucasian patients with late onset AD and exon 1 in a US study of late onset AD have been reported. Clinically diagnosed Japanese patients with AD and Japanese normal control subjects were assessed for the presence of polymorphisms of CST3. The authors could not confirm the previously reported association between CST3 polymorphisms and AD in Japan. Age had no effect on the CST3 genotype.